Since 2020 Sofie Boons has been collaborating with a physicist and crystal grower as part of her, recently completed, doctoral research. Her collaborator, Daniel Rytz, has been active in the field of crystals for optical, piezoelectric and other applications since 1977. In 2012, together with his partner Corinne Siegrist, he founded BREVALOR as a platform to develop crystals with novel properties for ornamental applications. One of the innovations he has been working on, are phosphorescent crystals. The materials BRG and BRB have similar properties to classical gemstones: their hardness allows them to be shaped and facetted, and they have the optical appearance of gems. This light-emitting gemstone material, capable of storing energy and generating its own light, is taking the quest to optimise light reflection in gemstones to a whole new dimension. In this episode, Sofie and Daniel discuss his career, the subject of crystal growth and his thoughts on the future of these and other novel materials for the jewellery industry.